| 大兴安岭扎兰屯地区晚古生代格根敖包组埃达克岩的发现及地质意义 |
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| 引用本文： | 张渝金,吴新伟,杨雅军,崔天日,江斌,郭威,张超,钱程,陈会军.大兴安岭扎兰屯地区晚古生代格根敖包组埃达克岩的发现及地质意义[J].地质与资源,2016,25(3):227-236. |
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| 作者姓名： | 张渝金 吴新伟 杨雅军 崔天日 江斌 郭威 张超 钱程 陈会军 |
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| 作者单位： | 1. 中国地质调查局 沈阳地质调查中心(沈阳地质矿产研究所), 辽宁 沈阳 110034;2. 吉林大学 地球科学学院, 吉林 长春 130061 |
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| 基金项目： | 中国地质调查局项目(1212011120664、1212011120665、1212011120666、12120113053900和1212011085210) |
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| 摘 要： | 大兴安岭中段扎兰屯地区晚古生代埃达克岩主要岩石类型为安山岩、粗面安山岩、英安岩和粗面英安岩,取得一个安山岩样品的LA-ICP-MS锆石U-Pb年龄为(316.9±2.4)Ma,代表火山岩喷发的年龄.岩石具有较高Si(Si O2=54.97%~63.80%),富碱并相对略富Na(Na2O/K2O1),富Al(Al_2O_3=14.97%~17.69%),高Sr(715.98×10~(-6)~2100×10~(-6)),低Y(12×10~(-6)~18.41×10~(-6))和Yb(1.02×10~(-6)~1.91×10~(-6))的特点.在原始地幔标准化蛛网图中,富集LREE,亏损HREE,Eu呈微弱正异常(δEu=0.97~1.30).同时Mg值介于0.35~0.57,平均0.46.总体特征属于高钾钙碱性埃达克岩(为C型埃达克岩的一种),来源于增厚的玄武质下地壳的部分熔融.扎兰屯地区晚古生代高钾钙碱性埃达克岩的发现,为兴安地块与松嫩地块的拼贴作用提供了新的线索,对正确认识区域地壳演化有着重要的构造意义,为本区寻找与埃达克岩有关的矿产提供了线索.
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| 关 键 词： | 埃达克岩 地球化学特征 晚古生代 大兴安岭中段 地质意义 |
| 收稿时间： | 2016-03-14 |
DISCOVERY AND GEOLOGICAL SIGNIFICANCE OF ADAKITIC ROCKS IN THE LATE PALEOZOIC GEGENAOBAO FORMATION IN ZHALANTUN AREA,MIDDLE DAXINGANLING MOUNTAINS |
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| ZHANG Yu-jin,WU Xin-wei,YANG Ya-jun,CUI Tian-ri,JIANG Bin,GUO Wei,ZHANG Chao,QIANG Cheng,CHEN Hui-jun,LI Wei,LI Lin-chuan,SI Qiu-liang.DISCOVERY AND GEOLOGICAL SIGNIFICANCE OF ADAKITIC ROCKS IN THE LATE PALEOZOIC GEGENAOBAO FORMATION IN ZHALANTUN AREA,MIDDLE DAXINGANLING MOUNTAINS[J].Geology and Resources,2016,25(3):227-236. |
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| Authors: | ZHANG Yu-jin WU Xin-wei YANG Ya-jun CUI Tian-ri JIANG Bin GUO Wei ZHANG Chao QIANG Cheng CHEN Hui-jun LI Wei LI Lin-chuan SI Qiu-liang |
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| Institution: | 1. Shenyang Institute of Geology and Mineral Resources, CGS, Shenyang 110034, China;2. College of Earth Sciences, Jilin University, Changchun 130061, China |
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| Abstract: | The Late Paleozoic adakites in Zhalantun area in the middle section of Daxinganling Mountains are composed of mainly andesite, trachyandesite, dacite and trachydacite. One of the andesite samples yields the zircon U-Pb age of (316.9±2.4) Ma by LA-ICP-MS, which represents the eruption age. The andesite has a high Si (54.97%-63.80%) and alkali content, with relatively high Na(Na2O/K2O>1). Besides, high Al(Al2O3=14.97%-17.69%) and Sr(715.98×10-6-2100×10-6)and low Y (12×10-6-18.41×10-6)and Yb (1.02×10-6-1.91×10-6)are also shown in this sample. The primitive mantle-normalized spider diagram of the andesite shows enriched LREE and depleted HREE, with slight positive Eu anomaly. The Mg# values range from 0.35 to 0.57, averagely 0.46. Generally speaking, this andesite belongs to the high-K calc-alkaline adakite (C-type adakite), which should originate from the partial melting of thickened basaltic lower crust. The discovery of this high-K calc-alkaline adakite in Zhalantun area provides a new clue for the amalgamation of Xinganling and Songnen massifs, which has a tectonic significance for understanding the regional crustal evolution, and therefore is useful for locating the mineral deposits related to adakite. |
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| Keywords: | adakite geochemistry Late Paleozoic Middle Daxinganling geologic implication |
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